Question for all you 1-Ton owners...

[5Tractorguy]

I'm looking to buy and other 1-ton this year and have some questions regarding transmissions. Currently have an '88 1-ton, 4WD, 5.7/TH400.

I don't do a lot of highway driving but on occasion I need to, whether it's an out of state trip picking up tractors or in state. To travel well at 65mph would be great. The TH400 in mine has never ran right, always slipped, so I never really knew what the average top speed for a 400 is. And I know a lot of this depends on diff gearing too.

-Those that own standard transmission trucks (low 1st 4-speeds), what is your top highway speed? What can you travel comfortably at?

-With a TH400/TH350 transmission highway speed?

Any input is appreciated! I know these are old trucks and aren't for speed, not looking to do 80+ here...